Determination of Residual Stresses in Brush-Plated Coatings by Mechanical and X-ray Techniques

The determination of residual stresses is studied in brush-plated nickel coatings of different thickness, deposited on brass strip substrates with two different dimensions. Residual stresses in the surface layer were found by the deformation method, displacement of the free end of the coated region of the cantilevered strip substrate or the axial strain of the free surface serving as experimental information. The x-ray diffraction technique was employed to determine residual stresses in specimens (8x10 mm) cut from the middle of the coated strip substrate by using lattice parameters measured for two different ψ values. Comparable values of residual stresses, 350-450 MPa and 280-480 MPa, were obtained in coating with a thickness of 45-110 μm by using the mechanical method and the x-ray diffraction technique respectively